nslookup -> getaddrinfo 사용 사례

#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <arpa/inet.h>
 
 
int main(int argc, char **argv)
{
        struct addrinfo hints;
        struct addrinfo *result, *rp;
        struct sockaddr_in *sin;
        struct sockaddr_in6 *sin6;
        int *listen_fd;
        int listen_fd_num=0;
 
        char buf[80] = {0x00,};
        int i = 0;
       /* if(argc != 2)
        {
                printf("Usage : %s [port]\n", argv[0]);
                return 1;
        }
     */

        memset(&hints, 0x00, sizeof(struct addrinfo));
 
        hints.ai_flags = AI_PASSIVE;
        hints.ai_family = AF_UNSPEC;
        hints.ai_socktype = SOCK_STREAM;
 
        if(getaddrinfo(argv[1], NULL, &hints, &result) != 0 )
        {
                perror("getaddrinfo");
                return 1;
        }
 
        for(rp = result ; rp != NULL; rp = rp->ai_next)
        {
                listen_fd_num++;
        }
        listen_fd = malloc(sizeof(int)*listen_fd_num);
 
        printf("Num %d\n", listen_fd_num);
        for(rp = result, i=0 ; rp != NULL; rp = rp->ai_next, i++)
        {
                if(rp->ai_family == AF_INET)
                {
                        sin = (void *)rp->ai_addr;
                        inet_ntop(rp->ai_family, &sin->sin_addr, buf, sizeof(buf));
                        printf("<bind 정보 %d %d %s>\n", rp->ai_protocol, rp->ai_socktype, buf);
                }
                else if(rp->ai_family == AF_INET6)
                {
                        sin6 = (void *)rp->ai_addr;
                        inet_ntop(rp->ai_family, &sin6->sin6_addr, buf, sizeof(buf));
                        printf("<bind 정보 %d %d %s>\n", rp->ai_protocol, rp->ai_socktype, buf);
                }
                if((listen_fd[i] = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol)) < 0)
                {
                        printf("Socket Create Error\n");
                }
                if(rp->ai_family == AF_INET6)
                {
                        int opt = 1;
                        setsockopt(listen_fd[i], IPPROTO_IPV6, IPV6_V6ONLY, (char *)&opt, sizeof(opt));
                }
 
                if(bind(listen_fd[i], rp->ai_addr, rp->ai_addrlen) != 0)
                {
                        if(errno != EADDRINUSE);
                        {
                                perror("bind error\n");
                                return 1;
                        }
                }
                if(listen(listen_fd[i], 5) != 0)
                {
                        perror("listen error\n");
                        return 1;
                }
        }
        freeaddrinfo(result);
        pause();
        return 1;
}